PVD system with remote arc discharge plasma assisted process

ABSTRACT

An arc coating system includes a coating chamber having a peripheral chamber wall, a top wall, and a bottom wall. The peripheral chamber wall, the top wall, and the bottom wall define a coating cavity and a chamber center. A plasma source is positioned at the chamber center wherein the plasma source comprises a central cathode rod and a plurality of cathode rods surrounding the central cathode rod. The coating system also includes a sample holder that holds a plurality of substrates to be coated. Characteristically, the sample holder rotatable about the chamber center at a first distance from the chamber center.

TECHNICAL FIELD

In at least on aspect, the present invention is directed to arcdepositions systems and related methods.

BACKGROUND

Physical vapor deposition (PVD) and low pressure chemical vapordeposition (CVD) sources are used for deposition of coatings and surfacetreatment. Over the last 25 years, cathodic arc deposition (i.e., a typeof physical deposition) has become established as a reliable source ofhighly ionized plasma for deposition of reacted as well as un-reactedcoatings from conductive target materials such as zirconium, titanium,chrome, aluminum, copper and alloys thereof. The highly ionized plasmaand the associated electron beam generated in the arc evaporationprocess is also used in such surface processing techniques as ionsputtering, etching, implantation and diffusion processes. In a typicalcathodic arc coating process, an electric arc vaporizes material from acathode target. The vaporized material then condenses on a substrate toform a coating.

Although cathodic arc systems work well, such systems are typicallylimited to only one or a few applications. Due the relatively highcapital expenses for coating systems, and arc depositions in particular,there is desire for any given system for be capable of operating in anumber of different applications. Such applications include sputteringonly, cathodic arc deposition only, sputtering plus cathodic arcsimultaneously, and the like.

Accordingly, there is a need for coating systems with improvedversatility.

SUMMARY

The present invention solves one or more problems of the prior art byproviding in at least one aspect, a coating system that includes aplurality of magnetrons surround a central cathode rod. The coatingsystem includes a coating chamber having a peripheral chamber wall, atop wall, and a bottom wall. The peripheral chamber wall, the top wall,and the bottom wall define a coating cavity and a chamber center. Aplasma source is positioned at the chamber center wherein the plasmasource comprises a central cathode rod and a plurality of cathode rodssurrounding the central cathode rod. The coating system also includes asample holder that holds a plurality of substrates to be coated.Characteristically, the sample holder rotatable about the chamber centerat a first distance from the chamber center.

In another embodiment, a coating system having external magnetic coilsis provided. The coating system includes a coating chamber having aperipheral chamber wall, a top wall, and a bottom wall. The peripheralchamber wall, the top wall, and the bottom wall define a coating cavityand a chamber center. A plasma source is positioned at the chambercenter wherein the plasma source comprises a central cathode rod. Thecoating system also includes a sample holder that holds a plurality ofsubstrates to be coated. The sample holder is rotatable about thechamber center at a first distance from the chamber center. A firstcoaxial magnetic coil is positioned externally to the coating chamberand a second coaxial magnetic coil is positioned externally to thecoating chamber.

Advantageously, the coating systems set forth above can be used for anumber of difference applications. In one example, the coating systemcan be adapted for plasma enhanced magnetron sputtering accompanied byboth ionization of metal-gaseous plasma by a remote arc dischargeestablished between central cathode rid and the remote anode located bythe peripheral chamber wall which is further enhanced by a hollowcathode plasma generating inside of the isolation shield. In anotherapplication, the coating system can be adapted for cathodic arc plasmadeposition alone or in combination with magnetron sputtering enhanced bya densified hollow cathode plasma generating within the isolationshield. In another application, the coating system can be adapted forion cleaning and ion surface conditioning in to hollow cathode gaseousplasma generating within a metal mesh negatively charged container. Instill another application, the coating system can be adapted for plasmaenhanced magnetron sputtering (PEMS).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross section and top view of a coating systemincluding at least one isolation shield and a plurality of cathode rods;

FIG. 2A is a schematic cross section and side view of a coating systemincluding at least one isolation shield and a plurality of cathode rods;

FIG. 2B is a schematic cross section and side view of a coating systemincluding at least one isolation shield perpendicular to the view ofFIG. 2A;

FIG. 2C is a schematic illustration the operation of the plurality ofcathode rods during sputtering;

FIG. 3 is a schematic cross section and top view of a coating systemwith external magnetic coils;

FIG. 4A is a side view of an isolation shield formed from parallel rods;and

FIG. 4B is a side view of an isolation shield formed from parallel rods.

DETAILED DESCRIPTION

Reference will now be made in detail to presently preferredcompositions, embodiments and methods of the present invention, whichconstitute the best modes of practicing the invention presently known tothe inventors. The Figures are not necessarily to scale. However, it isto be understood that the disclosed embodiments are merely exemplary ofthe invention that may be embodied in various and alternative forms.Therefore, specific details disclosed herein are not to be interpretedas limiting, but merely as a representative basis for any aspect of theinvention and/or as a representative basis for teaching one skilled inthe art to variously employ the present invention.

It is also to be understood that this invention is not limited to thespecific embodiments and methods described below, as specific componentsand/or conditions may, of course, vary. Furthermore, the terminologyused herein is used only for the purpose of describing particularembodiments of the present invention and is not intended to be limitingin any way.

It must also be noted that, as used in the specification and theappended claims, the singular form “a,” “an,” and “the” comprise pluralreferents unless the context clearly indicates otherwise. For example,reference to a component in the singular is intended to comprise aplurality of components.

The term “comprising” is synonymous with “including,” “having,”“containing,” or “characterized by.” These terms are inclusive andopen-ended and do not exclude additional, unrecited elements or methodsteps.

The phrase “consisting of” excludes any element, step, or ingredient notspecified in the claim. When this phrase appears in a clause of the bodyof a claim, rather than immediately following the preamble, it limitsonly the element set forth in that clause; other elements are notexcluded from the claim as a whole.

The phrase “consisting essentially of” limits the scope of a claim tothe specified materials or steps, plus those that do not materiallyaffect the basic and novel characteristic(s) of the claimed subjectmatter.

With respect to the terms “comprising,” “consisting of,” and “consistingessentially of,” where one of these three terms is used herein, thepresently disclosed and claimed subject matter can include the use ofeither of the other two terms.

Throughout this application, where publications are referenced, thedisclosures of these publications in their entireties are herebyincorporated by reference into this application to more fully describethe state of the art to which this invention pertains.

With reference to FIGS. 1, 2A, 2B, and 2C, schematic illustrations ofcoating systems having a plurality of cathode rods distributed about acentral cathode is provided. Coating system 10 includes a coatingchamber 12 defining a central coating cavity 14. In a refinement,coating chamber 12 includes peripheral chamber wall 16, top wall 18, anda bottom wall 20. In this context, “top” and “bottom” refer to therelative positions when the coating chamber is positioned in its designposition, i.e., the orientation to be used for coating a substrate.Chamber center 22 is a position approximately at the center of thechamber with respect to peripheral wall 16. In a further refinement,peripheral chamber wall 16 is cylindrical with a circular cross section.Peripheral wall 16 includes top edge 24 and a bottom edge 26. Top wall18 is adjacent to top edge 24 while bottom wall 20 is adjacent to bottomedge 26. In a refinement, the top wall 18 is a top flange positioned attop edge 24 of the peripheral chamber wall and bottom wall 20 is abottom flange positioned at bottom edge 26 of the peripheral chamberwall. Plasma source 30 is positioned at the chamber center. Sampleholder 32 holds a plurality of substrates 34 to be coated. Sample holder32 is rotatable along direction f₁ about the chamber center at a firstdistance d₁ from the chamber center.

As depicted in FIGS. 2A and 2B, plasma source 30 can include centralcathode rod 60 and central coil 62 surrounding central cathode rod 60.Central coil 62 is coaxially mounted about cathode rod 60. Cathode rod60 is powered by power supply 64 while central coil 62 is powered bypower supply 66. Control system 68 can be used to control the currentflowing throw cathode rod 60 and central coil 62. Typically, the currentflowing though is from 50 to 2000 A.

Still referring to FIGS. 1, 2A, 2B, and 2C, schematic illustrations of acoating system that includes a plurality of cathode sputtering rodsdistributed about a center cathode is provided. These rods canadvantageously be used for as magnetrons for magnetron sputtering. Inthis variation, coating system 10 includes a plurality of cathode rods72, 74, 76, and 78 surround plasma sources 30 (e.g., central cathode rod60 and central coil 62). In a variation, the plurality of cathode rodsincludes 1 to 10 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) rod-shapedcathodes having a longitudinal axis a₁ aligned parallel to theperipheral chamber wall. In another refinement, the plurality of cathoderods includes an even number (e.g., 2, 4, 6, 8, etc.) of rod-shapedcathodes having a longitudinal axis a₁ aligned parallel to theperipheral chamber wall. FIG. 3 depicts a situation where there or 4auxiliary cathode rods. Typically, each cathode rod of the plurality ofcathode rods are rotatable about the longitudinal axis a₂. The adjacentrods can be rotated in the same sense or opposite sense (i.e., clockwiseor counterclockwise). In a refinement, a plurality of blocking shields82, 84 such that a blocking shield is positioned between alternatingpairs of cathode rods in the plurality of cathode rods.

As shown in FIG. 2C, the electric current can be conducted along theaxis of the cylindrical magnetron sources with the currents along eachneighbor pair of cathode rods directed in opposite directions I₁ and I₂.In this case, a focusing magnetic field will be generated by the linearcurrents conducted along the axes of the magnetrons, the magnetic fieldlines of this magnetic field lie in the plane perpendicular to the axesof the plasma sources focusing the metal vapor arc plasma throughblocking shields 82, 84 away from the plasma source setup toward thesubstrates to be coated in the coating chamber. In this coatingdeposition, blocking shields 82, 84 are preferably position along themagnetic force lines generating by the linear currents conducted alongthe magnetron sputtering sources, which repels the positively chargedions away from the area between the baffles and the cathodic arc sourcetoward the substrates to be coated in the deposition area of the coatingchamber.

In a refinement, coating system 10 includes one or more isolationshields. First isolation shield 40 is positioned about the chambercenter at a second distance d₂ from the chamber center. Typically,second distance d₂ is greater than the first distance. Alternatively,second distance is less than the first distance. The first isolationshield 40 is typically negatively charged. For this purpose, system 10includes DC power supply 42 which has positive terminal 44 and negativeterminal 46 which is connected to first isolation shield 40 or byconnection to the RF power supply 47 in which case the negative autopolarization potential will create the RF hollow cathode effect insideof the hollow cathode container. Vacuum system 48 is in fluidcommunication with coating chamber 12 and is used to maintain a vacuumduring coating deposition. In a variation described below in moredetail, remote anodes 58 are positioned at a third distance d₃ from thechamber center moved away from the container established by firstisolation shield 40.

First isolation shield 40 can establish a hollow cathode containerenclosing both centrally located metal vapor plasma sources andsubstrates 34. It allows to increase the density and electrontemperature as well as concentration of high energy electrons within thearea inside of negatively charged first isolation shield 40 during allstages of the coating deposition process as compared to a system nothaving the isolation shield: (i) ion cleaning and ion surface conditionstage in the hollow cathode gaseous plasma generating within the hollowcathode container; (ii) plasma enhanced magnetron sputtering (PEMS) modewhen magnetron sputtering is providing win the hollow cathode plasmacloud generating by the hollow cathode container; (iii) the plasmaenhanced magnetron sputtering accompanied by both ionization of themetal-gaseous plasma by the remote arc discharge established between thecylindrical cathode of the cathodic arc source and the remote anodeslocated by the chamber walls which is further enhanced by the hollowcathode plasma generating inside of the negatively charged metalcontainer enclosing both centrally located plasma sources and substrates34 in the coating deposition area; (iv) the cathodic arc plasmadeposition mode along or in combination with magnetron sputteringenhanced by the densified hollow cathode plasma generating with thenegatively charged hollow cathode container.

In a variation, coating system 10 further includes a second isolationshield 50. Second isolation shield 50 is positioned at a fourth distanced₄ from the chamber center that is less than the first distance d₁. In afurther refinement, the substrates are biased at the same potential assecond isolation shield 50. DC voltage supply 52 can be used for thispurpose. In one refinement, first isolation shield 40 and secondisolation shield 50 are each independently a metal mesh screen.Typically, first isolation shield 40 is outer metal mesh screen andsecond isolation shield 50 is an inner metal mesh screen. Typically, theouter mesh screen and the inner mesh screen have openings that are eachindependently from 1 mm to 50 mm. In a refinement, the outer mesh screenand the inner mesh screen have openings that are each independently from5 mm to 20 mm. wherein substrates to be coated are enclosed in acontainer established by the first isolation shield separating thesubstrates from the peripheral chamber wall and the second isolationshield separating substrates from a central cathode rod. The openingssmaller than 1 mm can block plasma from flowing across the metal meshwall, while the opening greater than 50 mm can mitigate the productionof dense plasma by the hollow cathode effect.

When second isolation shield 50 is present, the substrates 34 areenclosed in the negatively DC pulsed powered metal mesh containerestablished between the first isolation shield (e.g., an outer meshscreen) separating the substrates 34 from peripheral wall 16 and secondisolation shield 50 (e.g., inner metal mesh screen) separatingsubstrates 34 from the centrally positioned plasma sources. Thesubstrates can be bias to the same potential as first isolation shield40 and/or second isolation shield 50 by simply electrically connectingthem to the metal mesh screen, or, alternatively, the bias potential ofthe substrates 34 can be different from the potential of the metal meshscreen container, which can be provided by the independent substratebias power supply (not shown).

In a variation, first isolation shield 40 does not have to providecomplete separation of the inside area from the grounded chamber walls.For instance, the top and the bottom of the container can be completelyor partially opened to the chamber with the isolation shield removed.Alternatively, first isolation shield 40 and/or second isolation shield50 can partially can be made of the metal sheet without openings. Forinstance, the top and the bottom walls of the metal mesh container canbe made of metal sheet without openings or can be open to the chamberwalls.

In another refinement as depicted in FIGS. 3A and 3B, one or both offirst isolation shield 40 and second isolation shield 50 include aplurality of parallel rods typically with a distance d_(r) betweenneighbor rods 54 from 1 mm to 50 mm. Crossbars 56 can be used to holdrods 54 about chamber center 22.

As set forth above, coating system 10 can further includes remote anode58 which can be positioned at a fourth distance d₄ from the chambercenter that is greater than the first distance d₁ and the seconddistance d₂. In a refinement, system 10 further includes one or moreadditional remote anodes 54 distributed along peripheral wall 16.Peripheral wall 16 can optionally include recesses 60 for positions suchremote anode. The presence of a remote anode allows the coating systemto be operated in a remote arc assisted magnetron sputtering (RAAMS)mode as set forth in U.S. Pat. No. 9,412,569; the entire disclosure ofwhich is hereby incorporated by reference.

With reference to FIG. 4, a schematic illustration of a coating systemhaving external coaxial magnetic coils is provided. In this variation,the central coil 62 which is placed in the cavity of coating chamber 12depicted in FIGS. 2A and 2B is absent. Instead, coaxial magnetic coilsare placed external to coating chamber 12 but proximate to peripheralwall 16. For example, FIG. 5 shows first coaxial magnetic coil 90positioned proximate to the first wall external to the coating chamberand second coaxial magnetic coil 92 positioned proximate to the secondwall external to the coating chamber.

The following examples illustrate the various embodiments of the presentinvention. Those skilled in the art will recognize many variations thatare within the spirit of the present invention and scope of the claims.

Example 1. RAAMS Deposition of TiN Coatings

The coating system shown in FIG. 1 equipped with 4 cylindricalmagnetrons and centrally located cylindrical cathodic arc source is usedfor this coating deposition process. Both the magnetrons and thecathodic arc source are equipped with titanium targets. At the beginningstage of ion cleaning the argon as plasma created gas is introduced intothe vacuum chamber to gas pressure ranging from 1 to 10 mTorr. Theprimary arc discharge is ignited by mechanical trigger between thesurface of the cathodic arc target and grounded shields positionedbetween the magnetron sources. The remote arc discharge is then ignitedbetween the cylindrical cathode target and remote anodes located by thewalls of the vacuum coating deposition chamber. The current of theprimary arc is set at 140 A while its voltage is oscillating within therange from approximately 25V to approximately 30V. The current of theremote arc is set at 400 A while its voltage is oscillating within therange from approximately 60V to approximately 80V. The current of theremote arc propagates from the cathode target throughout the chevronshield, which is not transparent for the heavy components of the vacuumarc plasma (metal ions, atoms and macroparticles) while allows theelectron current of the remote arc discharge to be conducted from thecylindrical cathode target toward the remote anodes located by thecoating chamber walls. The substrates to be coated are loaded on therotary table, which allow them to rotate around the center of thecoating chamber and, at the same time, around their own axes. The biasvoltage of −300V is applied to the rotary table with substrates to becoated. The ion cleaning stage continuous for 30 min followed by remotearc assisted magnetron sputtering (RAAMS) deposition stage. At thebeginning of the deposition stage the nitrogen is added to the chamberto make about 30% N2/balance argon mixture at the pressures ranging from2 to 5 mTorr. The magnetrons are turned on by magnetron power supplieswith power density approximately 5 W/cm2 of the magnetron sputteringtarget. The substrate bias during TiN coating deposition stage isreduced to 100V. The deposition of TiN coating is lasting 3 hrs. fordeposition of 5 μm thick TiN coating.

Example 2. RAAMS Deposition of TiN/DLC 2-Segment Coatings

The coating system shown in FIG. 1 equipped with 4 cylindricalmagnetrons and centrally located cylindrical cathodic arc source is usedfor this coating deposition process. Both the magnetrons and thecathodic arc source are equipped with titanium targets. The metal meshcage is electrically connected to the rotary table with substrates to becoated to maintain equal potential of the cage and substrates. The cageand rotary table are connected to DC bias power supply and high voltageDC pulse power supply via switches so either of these two power suppliescan be connected to the metal cage and rotary table with substrates tobe coated at different stages of the coating deposition process. At thebeginning stage of ion cleaning the argon as plasma created gas isintroduced into the vacuum chamber to gas pressure ranging from 1 to 10mTorr. The primary arc discharge is ignited by mechanical triggerbetween the surface of the cathodic arc target and grounded shieldspositioned between the magnetron sources. The remote arc discharge isthen ignited between the cylindrical cathode target and remote anodeslocated by the walls of the vacuum coating deposition chamber. Thecurrent of the primary arc is set at 140 A while its voltage isoscillating within the range from approximately 25V to approximately30V. The current of the remote arc is set at 400 A while its voltage isoscillating within the range from approximately 60V to approximately80V. The current of the remote arc is propagating from the cathodetarget throughout the chevron shield, which is not transparent for theheavy components of the vacuum arc plasma (metal ions, atoms andmacroparticles) while allows the electron current of the remote arcdischarge to be conducted from the cylindrical cathode target toward theremote anodes located by the coating chamber walls. The substrates to becoated are loaded on the rotary table, which allow them to rotate aroundthe center of the coating chamber and, at the same time, around theirown axes. The DC pulse power supply is disconnected from the cage and DCbias power supply is connected to the cage to apply DC bias voltage of−300V to the rotary table with substrates to be coated during ioncleaning stage. The ion cleaning stage continuous for 30 min followed byremote arc assisted magnetron sputtering (RAAMS) deposition stage. Atthe beginning of the deposition stage the nitrogen is added to thechamber to make about 30% N2/balance argon mixture at the pressuresranging from 2 to 5 mTorr. The magnetrons are turned on by magnetronpower supplies with power density approximately 5 W/cm2 of the magnetronsputtering target. The substrate bias during TiN coating depositionstage is reduced to 100V DC. The deposition of TiN coating is lasting 1hrs. for deposition of 1.5 μm thick TiN coating segment. Aftercompleting the TiN coating segment deposition stage, the magnetrons areturned off and argon/nitrogen mixture as reactive gas atmosphere isreplaced with acetylene to total pressure of 15 mTorr. The DC bias powersupply is disconnected from the cage and DC pulse bias power supply isconnected to the cage and simultaneously to the rotary table withsubstrates to be coated. The negative DC pulse voltage with −5 kVamplitude and 30 kHz frequency is applied to the cage and rotary tableto establish the hollow cathode enhanced dense plasma cloud duringdeposition of the top DLC coating segment. The deposition of the DLCsegment is lasting 4 hrs. resulting in deposition of 5 μm thick DLC topsegment layer.

Example 3. RAAMS-Cathodic Arc Hybrid Deposition of TiSiNC NanocompositeCoatings

The coating system shown in FIG. 1 equipped with 4 cylindricalmagnetrons and centrally located cylindrical cathodic arc source is usedfor this coating deposition process. Both the magnetrons and thecathodic arc source are equipped with titanium targets same as inExample 1. The adjustable venetian baffles are used between twomagnetrons of two opposite pairs of magnetrons, while between magnetronsof adjacent pairs of magnetrons the solid metal shield is installed asshown in FIG. 1. At the beginning stage of ion cleaning the argon asplasma created gas is introduced into the vacuum chamber to gas pressureranging from 1 to 10 mTorr. The primary arc discharge is ignited bymechanical trigger between the surface of the cathodic arc target andgrounded shields positioned between the magnetron sources. At the stageof ion cleaning the venetian baffles are slightly open blocking theheavy components of the cathodic arc from propagating into the coatingdeposition area between centrally located plasma sources and the chamberwalls while allow the electron current to freely propagate through thearray of the venetian baffles along the remote arc discharge establishedbetween the cylindrical cathode target and the remote anodes positionedby the chamber's walls. The remote arc discharge is then ignited betweenthe cylindrical cathode target and remote anodes located by the walls ofthe vacuum coating deposition chamber. The current of the primary arc isset at 140 A while its voltage is oscillating within the range fromapproximately 25V to approximately 30V. The current of the remote arc isset at 400 A while its voltage is oscillating within the range fromapproximately 60V to approximately 80V. The substrates to be coated areloaded on the rotary table, which allow them to rotate around the centerof the coating chamber and, at the same time, around their own axes. Thebias voltage of −300V is applied to the rotary table with substrates tobe coated and, simultaneously to the metal mesh cage electricallyconnected to the rotary table by the DC bias power supply, which isswitched on, while the high voltage DC pulse power supply is switchedoff. The ion cleaning stage continuous for 30 min followed by remote arcassisted magnetron sputtering (RAAMS) deposition stage. At the beginningof the TiNSiC nanocomposite coating deposition stage the nitrogen andtrimethylsilane (3MS) are added to the argon in the processing chamberto make the reactive gas mixture of the 30% N2/10%3MS/balance argoncomposition at the pressures ranging from 2 to 5 mTorr. The magnetronsare turned on by magnetron power supplies with power densityapproximately 5 W/cm2 of the magnetron sputtering target. The DC biaspower supply is switched off while the high voltage DC pulse powersupply is switched on and set to apply 5 kV negative pulses with 30 kHzrepetition frequency. The electric current of about 300 A is conductedalong the cylindrical magnetron, having its directions switched to theopposite in each neighbor magnetron as shown in FIGS. 15j and 15k toprovide focusing magnetic field between the neighbor magnetrons asillustrated by magnetic force lines with arrows in FIGS. 15i and 15k .The position of the strips of the venetian baffles are adjusted to makethe surface of the baffles generally tangential to the focusing magneticfield as shown in FIG. 15k , creating the plasma transporting corridorsbetween the neighbor strips of the venetian baffles array. Thedirections of the magnetron sputtering metal atoms flow and themagnetically focusing cathodic arc metal vapor plasma are coincided toprovide cathodic arc/magnetron hybrid process of deposition ofnanocomposite TiNSiC coating, which is lasting 5 hrs. for deposition of20 μm thick TiNSiC nanocomposite coating.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the invention. Rather,the words used in the specification are words of description rather thanlimitation, and it is understood that various changes may be madewithout departing from the spirit and scope of the invention.Additionally, the features of various implementing embodiments may becombined to form further embodiments of the invention.

What is claimed is:
 1. A coating system comprising: a coating chamberhaving a peripheral chamber wall, a top wall, and a bottom wall, theperipheral chamber wall, the top wall, and the bottom wall defining acoating cavity and a chamber center; a plasma source positioned at thechamber center wherein the plasma source comprises a central cathode rodand a plurality of cathode rods surrounding the central cathode rod,each a longitudinal axis aligned parallel to the peripheral chamberwall; and a sample holder that holds a plurality of substrates to becoated, the sample holder rotatable about the chamber center at a firstdistance from the chamber center, wherein each cathode rod in theplurality of cathode rods are rotatable about the longitudinal axis. 2.The coating system of claim 1 further comprising a central coilsurrounding the central cathode rod.
 3. The coating system of claim 1further comprising at least one remote anode positioned at a seconddistance from the chamber center proximate to the peripheral chamberwall.
 4. The coating system of claim 1 wherein the plurality of cathoderods includes 1 to 10 rod-shaped cathodes.
 5. The coating system ofclaim 1 further comprising a plurality of blocking shields such that ablocking shield is positioned between alternating pairs of cathode rodsin the plurality of cathode rods.
 6. The coating system of claim 1further comprising a first isolation shield interposed between thesample holder and the peripheral chamber wall and a second isolationshield interposed between the plasma source and the sample holder. 7.The coating system of claim 6 wherein the first isolation shield is anouter metal mesh screen and the second isolation shield is an innermetal mesh screen.
 8. The coating system of claim 7 wherein substratesare biased to a same potential as the inner metal mesh screen.
 9. Thecoating system of claim 8 further comprising a DC power supply having apositive terminal and a negative terminal, the negative terminal beingconnected to the first isolation shield.
 10. The coating system of claim1 wherein the top wall is a top flange positioned at a top edge of theperipheral chamber wall and the bottom wall is a bottom flangepositioned at a bottom edge of the peripheral chamber wall.
 11. Acoating system comprising: a coating chamber having a peripheral chamberwall, a top wall, and a bottom wall, peripheral chamber wall, the topwall, and the bottom wall define a coating cavity and a chamber center;a plasma source positioned at the chamber center wherein the plasmasource comprises a central cathode rod and a plurality of cathode rodssurrounding the central cathode rod; a sample holder that holds aplurality of substrates to be coated, the sample holder rotatable aboutthe chamber center at a first distance from the chamber center; and afirst coaxial magnetic coil positioned externally to the coating chamberand a second coaxial magnetic coil positioned externally to the coatingchamber, wherein each cathode rod in the plurality of cathode rods arerotatable about a longitudinal axis.
 12. The coating system of claim 11wherein the first coaxial magnetic coil is positioned proximate to theperipheral chamber wall and the second coaxial magnetic coil ispositioned proximate to the peripheral chamber wall.
 13. The coatingsystem of claim 11 further comprising a central coil surrounding thecentral cathode rod.
 14. The coating system of claim 11 furthercomprising at least one remote anode positioned at a second distancefrom the chamber center proximate to the peripheral chamber wall. 15.The coating system of claim 1 further comprising a plurality of blockingshields such that a blocking shield is positioned between alternatingpairs of cathode rods in the plurality of cathode rods.
 16. The coatingsystem of claim 11 further comprising a first isolation shieldinterposed between the sample holder and the peripheral chamber wall anda second isolation shield interposed between the plasma source and thesample holder.
 17. The coating system of claim 16 wherein the firstisolation shield is an outer metal mesh screen and the second isolationshield is an inner metal mesh screen.